Private university Carnegie Mellon has written up an interesting method for keeping your passwords safe from keyloggers at public computers. The trick:

Between successive keys of the password we will enter random keys. In the spirit of chaffing and winnowing, the string that the keylogger receives will contain the password, but embedded in so much random junk that discovering it is infeasible.

The idea is, for each character of your password you type, you also type several random characters in another field in your browser. Using this method, the authors demonstrate how a password like snoopy2 becomes spqmlainsdgsosdgfsodgfdpuouuyhdg2 in the eyes of a keylogger. Of the five keylogging programs tested, none of them captured the correct passwords when this method was employed. While this trick does not ensure safety from a keylogger (check out the digg comments for more good suggestions for beefing up this method), it certainly will give you added security if you need to log into anything from a public computer.